Nebulization of fluids



May 20, 1930. c. L. RILEY 1,759,629

NEBULIZATION OF FLUIDS Filed March 51', 1926 HHHH I VENT CHAN] Pug 1yRQILEfi/ JAM.

" v XTTORNEYS' Patented May 20, 1930 UNITED' STATES PATENT OFFICECHAMPLAIN L. RILEY, OF NORTH PLAINFIELD, NEW JERSEY, ASSIGNOR TO INDUS-NEW YORK TRIAL ASSOCIATES, INCORPORATED, OF NEW YORK, N. Y., A.CORPORATION OF NEBU 'LIZATION OF FLUIDS Application filed March 31,1926.Serial No. 98,838.

' My invention relates to the nebulization of fluids, and particularlyto nebulization effected byhigh speed rotors. The object of my inventionis to effect nebulization of a fluid 5 stream'by centrifugal dischargeof the fluid simultaneously and with substantial uniformity at allpoints around the periphery of the rotor, and also 'to positivelyimpelthe .7 fluid at the peripheral linear speed of the rotor so that thefluid is discharged at such speed, augmented bythe velocity ofcentrifugal off-throw.

One of: he difficulties encountered on centrifugal dispersion of fluidwhich is fed in a stream to a centrifugal dis ersing unit, such as aplane disc rotor, arises rom the fact that the major portion of thestream is discharged at the rotor within a more or lessrestrictedarcuate area determined by the period of time required for the liquid totravel from its point of incidence adjacent the axis of the rotor to theperipheral throw-off point. The throw-off area is not sharply defined,since the liquid as it travels outwardly under the influence "ofcentrifugal force, is more or less dispersed over the surface of therotor. There 'is however, a point of maximum discharge, from which thedischarge tapers off in both directions around the periphery of therotor. There is also a variation in the size and velocity of theparticles discharged at the different peripheral points. This conditionis not favorable for spray drying. Uniformity of size in the particlesof the nebula, and unithe rotor, is the ideal condition, not only withrespect to the product itself, but also with respect to the action uponthe nebula of the current of gas passing through the drying chamber.

My invention effects such a uniform distribution and is applicable toall fluids, not only to mobile fluids, but also to thick or viscousfluids, such as concentrates, muds, etc'., which are only sluggishlymobile.

My underlying thouwht' is to gather the stream'in an annulus fiom whichthe fluid escapes evenly in all directions by centrifugal force throughimpellers which positively drive the fluid at the high speed of theformity of discharge in all directions around rotor,- and discharge itat this speed, augmented by the velocity of centrifugal offthrow. Therotor is driven at.high speed, say from 5,000 to 10,000 revolutions perminute or more, and the impellers are preferably shaped to effect thedischarge of the fluid at even greater velocity than the rotor under theinfluence of centrifugal force.

In the accompanying drawing Fig. l is a vertical section through a rotorin which my invention is embodied in one form; I

Fig. 2 is a broken section on the line 2-2, Fig. 1;

Fig. 3 is a partial vertical section illustratinga modifiedconstruction;

Fig. 4 is a vertical section illustrating another modification and tFig. 5 is a partial section illustrating still another modification.

In the form shown in Figs. 1 and 2 the rotor comprises a hub 15, a web16 extending therefrom, and a heavy peripheral rim 17, the innerperiphery of which is concaved to afford'a channel 18. The rotor ispreferably cut from a cylindrical disc of metal, such as tool steel,which has sufficient tensile strength to withstand the heavy stresses towhich it is subjected byfiits very rapid rotation. The heavy rim 17exerts a flywheel effect, which stabilizes the rotor during operation.

Upon the upper surface of the rim 17 are secured (or cut from a block) aseries of i peller surfaces or vanes 19, the inner margins 20 of whichare preferably sharpened to an edge. The leading faces of the vanes areconcaved, as at 21, and the outer or throwoff margins 22 are preferablyslightly in ad? The rotor isclamped to the shaft 24by nuts I 26 on pin27, which passes axially through the ballhub l and cupped bearing block28.

In operation the fluid is delivered in a stream through spout to the web16, over which it spreads and is outwardly distributed to the channel 18in which it gathers. A fluid annulus builds up within the channel 18under the influence 'of centrifugal force, until the channel is filled,whereupon it overflows simultaneously at all points around'itsperiphery, The overflow 'now moves outwardly along the upper surface ofthe rim 17 under the action of centrifugal force. Inasmuch as the liquidhas not yet attained the speed ofrotation .of the rim 17 the overflowfrom the channel is encountered by the vanes 19 and positively propelledthereby at the linear speed of rotation of the unit. At its peripheryits speed approximates two miles or more per minute. Travelling outwardalong the leading faces of the vanes under the action of centrifugalforce, theliquid is not only attenuated by spreading vertically over thefaces'of the vanes, but its linear speed is actually accelerated beyondthat of the rotor by reason of the forward inclination of the outermargins of the vanes. Consequently the dischar e velocity of the liquidis even greater than the lineal velocity of the rotor periphery, byreason of the augmented velocity due to centrifugal off-fling. Theforces of disassociation thus imparted to the liquid, combined .withtheir impact against the surrounding atmosfplhere, result in theproduction of a very e nebula which is ideal for spray drying purposes.Moreover, the distribution of the nebula onall sides of therotor fillsthe active area ofthe drying chamber uniformly, and evenly loads thecurrent of gas flowing therethrough. Uniformity of product not hithertoattained also results from the conditions stated.

In ,Figj 3 I have indicated a modification of construction in which therim 29 extends both above and below the web 30, the latter mit the fluidto fill the channel 32, which now also extends both above and'below theweb. ,From this channel the fluid escapes at both margins to the upperand lower surfaces of the rim, and to the vanes 19 and 19' thereon. The0 eration of this apparatus is substan- 2 and 3 but the output capacityof the unit is doubled.

In Fig. 4' another modification is shown in which the web 16 merges intoan outwardly inclined surface 33 instead of into a channel such as 18.In a construction of this type the retardation, of outward dispersal ofthe fluid from the web 16 is not so marked as in the case'of a channelsuch as that first described;

. but the incline 33 does serve as a distributing baflle even in thecase 'of mobile. fluids, by which an even distribution thereof to the impeller vanes is efi'ected. The construction is more particularlysuitablefhowever, for the handling of I heavy or slug shly mobilefluids, upon which the retartfiiig action of the incline 33 is moremarked. The degree of inclination may be varied to meet the re-'quirements of the fluid to be handled, being in some cases more markedthan shown in the 3 upper and lower mar ins of the rotor; Here I the web16 merges at'its outer, periphery into upwardly inclined facets 34 andalternate downwardly inclined facets 35, the former leading to the upperseries of vanes 19,-and' the latter leading the fluid through ports 36;

modified the construction in the web to a lower series of vanes 19'.

It will be realized that the shape of the vanes 19 may be modified inmany ways to produce the same or different effects, while stillembodying the thoughts which underlie my invention. Similarly theparticular shape'of the rotor unit as a whole'may be varied,while stillaccomplishing my results.

and practicing the features of my improved imitahod by which they areattained.

part to the rotor construction, certain fea tures of which areillustrated in Figure 5 of this case.

With the understanding, therefore, that the foregoing description andthe accom panying drawings illustrate only certain em odiments of mythoughts in certain ways of carrying out my method, I claim,

1. A high speed centrifugal nebulizer unit comprising a peripheral ringof impeller vanes, a web lying radially inward of said vanes, said webbeing substantially radial and adapted to receive and centrifugally dis-'perse a fluid streamfed thereto, and means intermediate said web andvane ring to receive said dispersed fluid and to distribute.

copending application Serial No'. 97,136, filed March 24, 1926, isdirected in 3. A high speed centrifugal nebulizeruni-t comprising arotor having a peripheral ring of impeller vanes, and means for feedingfluid to the inner margins of said vanes for centrifugal dispersalthereby, said vanes hav ing their peripheral margins arranged radiallyin advance of their inner margins to accelerate the off-throw velocityof the fluid.

- 4. A high speed centrifugal nebulizing rotor having a centralsubstantially radial dispersing surface, a distributingsurfacecircumferentially in extension of said dispersing surface, and a seriesof impeller vanes around said distributing area, said vanes beingaxially spaced from the-periphery of the distributing area.

5. A high speed centrifugal nebulizing rotor having a centralsubstantially radial dispersing surface, a distributing surfacecircumferentially in extension of said dispersing surface, and a seriesof impeller vanes around said distributing area, said vanes beingaxially spaced from the periphery of the distributing area, togetherwith a hood confining the fluid to the impeller vanes.

6. A high speed centrifugal nebulizing rotor having a centralsubstantially radial dispersing surface, a distributing surfacecircumferentially in extension of said dispersing surface, and a seriesof impeller vanes around said distributing area, said vanes beingaxially spaced from the periphery of the distributing area, togetherwith a hood confining the fluid to the impeller .vanes, 'said hoodextending radially inward beyond the inner margins of said vanes.

In testimony whereof I have signed my name to this specification.

GHAMPLAIN L. RILEY."

